Disposable wand and sensor for orthopedic alignment

ABSTRACT

A disposable tool suitable for use in orthopedic alignment comprises a sensor ( 101 ) communicatively coupled to the wand ( 102 ) to register points of interest on a first and second bone and transmit location data related to the points of interest to the sensor ( 101 ) to assess orthopedic alignment with the points of interest. A display via a wireless connection to the tool reports and visually displays alignment information in real-time. The wand ( 102 ) and the sensor ( 101 ) each have at least two ultrasonic transducers. The wand ( 102 ) has a housing fits in a hand and includes a tip ( 134 ) for identifying and registering a location. The wand ( 101 ) can be attached to a mount in a predetermined position within the surgical field during a portion of the alignment procedure. Sensor ( 101 ) and wand ( 102 ) remain within the surgical field throughout the surgery and are disposed of after use in surgery.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of U.S. provisional patentapplication No. 61/291,725 filed the of Dec. 31, 2009, the disclosure ofwhich is incorporated herein by reference in its entirety. Thisapplication also claims the benefit of U.S. patent application Ser. No.12/901,094 filed the of Oct. 8, 2010, the disclosure of which isincorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to orthopedic medical devicesand more specifically to portable assisted navigation surgical tools.

BACKGROUND

A total knee replacement is a surgical procedure whereby the diseasedknee joint is replaced with artificial material and prostheticcomponents. The knee is a hinge, which provides motion at the pointwhere the femur meets the tibia. During a total knee replacement, thedistal end of the femur bone is removed and replaced with a femoralcomponent. The proximal end of the tibia is also removed and replacedwith a tibial component. Depending on the condition of the kneecapportion of the knee joint, a button may also be added under the kneecapsurface.

During total knee replacement surgery it is imperative that the bonecuts on the femur and tibia are made to result in proper alignment. Thealignment ensures proper balance and straightness of the leg. The bonecuts can be made with use of physical guides and jigs, and morerecently, with significant success, by way of highly accurate computerassisted systems.

A need however can arise for low cost portable and disposable surgicaltools to provide assisted alignment in orthopedic surgical procedures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts an exemplary illustration of a portable alignment systemin accordance with one embodiment;

FIG. 1B depicts a wireless sensor for assisted alignment in accordancewith one embodiment;

FIG. 1C depicts a wireless wand for assisted alignment in accordancewith one embodiment;

FIG. 1D depicts a diagram for wireless wand registration in accordancewith one embodiment;

FIG. 1E depicts an exemplary sensory timing diagram in accordance withone embodiment;

FIG. 1F is an exemplary method for assisted guidance navigation inaccordance with one embodiment;

FIG. 1G depicts an exemplary display for assisted guidance navigation inaccordance with one embodiment;

FIG. 2A depicts an exemplary Graphical User Interface for tracking asensor in accordance with one embodiment;

FIG. 2B depicts an exemplary Graphical User Interface for identifying afemur head from rotational movement in accordance with one embodiment;

FIG. 2C depicts an exemplary Graphical User Interface for mapping andreporting leg movement in accordance with one embodiment;

FIG. 2D depicts an exemplary Three-Dimensional (3D) User Interface forspherical centroid identification of a femur head in accordance with oneembodiment;

FIG. 2E depicts an exemplary Three-Dimensional (3D) User Interface fororthopedic alignment in accordance with one embodiment;

FIG. 3 depicts an exemplary diagram for identifying a femur head viahand-held ultrasound scanning in accordance with one embodiment;

FIG. 4A depicts a disposable device for assisted alignment in accordancewith one embodiment;

FIG. 4B depicts a block diagram of components of the disposablealignment device in accordance with one embodiment;

FIG. 4C is an exemplary method for assisted guidance navigation inaccordance with one embodiment;

FIG. 5A depicts an exemplary communication system for one of severalembodiments of the alignment system in accordance with one embodiment;

FIG. 5B depicts an exemplary diagram for event services and monitoringof smart orthopedic implants in accordance with one embodiment;

FIG. 6 depicts an exemplary diagrammatic representation of a machine inthe form of a computer system within which a set of instructions, whenexecuted, may cause the machine to perform any one or more of themethodologies disclosed herein;

FIG. 7 is an illustration of a portable communication device having aGUI displaying alignment data in accordance with an exemplaryembodiment;

FIG. 8 is an illustration of the wand retained in a mount in accordancewith an exemplary embodiment; and

FIG. 9 is an illustration of knee prosthetic components in accordancewith an exemplary embodiment.

DETAILED DESCRIPTION

Embodiments in accordance with the present disclosure provide anapparatus and method of assisted guidance navigation for surgicalassisted alignment.

In one embodiment, a disposable tool suitable for use in orthopedicsurgery comprises a primary sensor and a wand to register points ofinterest on a first and second bone. The wand can be attached to acutting jig for reporting an orientation with respect to anatomicalalignment. The primary sensor and wand use ultrasonic sensing andtracking to determine their relative location to one another includingthe cutting jig when attached; both of which are wireless. Based on theregistered points of interest, the primary sensor can then assess andreport parameters related to the orientation of the cutting jig forestablishing cutting angles to align the first and second bone. Theprimary sensor can communicate with a remote (optional) communicationdevice via a wireless connection to report and visually displayalignment information in real-time.

Ultrasonic tracking and navigation can provide certain benefits overconventional available Computer Assisted Surgery (CAS) systems.Commercial CAS systems are based on different navigation principles(e.g., active or passive optical or electromagnetic) where preciseintra-operative orientation is provided by high-resolution imagingtechniques (e.g., computed tomography (CT), magnetic resonance imaging(MRI)). These systems generally require the placement of fiducialmarkers, CT or MRI imaging, data transfer to the operating room (OR),and identification and registration of the fiducials. They are alsosensitive to deviations in light intensity, contrast, and reflections.When performing these preparatory and practice steps, each platform hasindividual needs and a number of potential deficiencies influencing theaccuracy of the system.

CAS platforms generally consist of three main parts: a mobileworkstation, a position interface (e.g., camera system) and aninstrument pointer. The mobile workstation is the hub between theposition interface and the instrument pointer. It is generallypositioned away from the surgical area yet close enough to track theinstrument pointer. Although it requires minimal space in the operatingroom and is sufficiently mobile, it is generally a capital expense thatis maintained on-site. The instruments must be sterilized with each useand the sophisticated optical components are custom made.

The ultrasonic disposable tool in contrast comprises a primary sensorand wand that are both wireless and can communicate directly with oneanother; no mobile workstation is required between the two. Constructedwith low-cost ultrasonic transducers and electronic components it issuitable for up to 2-4 hours of use and can thereafter be disposed,thereby incurring less hospital support and overhead.

FIG. 1A depicts an exemplary embodiment of a portable wireless alignmentsystem 100 suitable for use as an alignment tool in orthopedic surgery.The system 100 includes a primary sensor 101, a wand 102, and a portablecommunication device 104; all of which can be wireless. In oneembodiment, the sensor 101 and wand 102 each have at least twoultrasonic transducers to support the identification of a location inthree-dimensional space. One example of providing sensory feedback in anavigated workflow with the sensorized tools is disclosed in U.S. patentapplication Ser. No. 12/900,662 entitled “Navigation Device ProvidingSensory Feedback” filed Oct. 8, 2010; the entire contents of which arehereby incorporated by reference.

As shown, sensor 101 and wand 102 each have three ultrasonictransducers. In one, embodiment, the wand 102 transmits ultrasonicsignals and sensor 101 detects ultrasonic signals. In a surgicalsetting, system 100 measures time of flight and differential time offlight of the transmitted ultrasonic signals for location determinationwithin a surgical field of an operating room. A trigger system isprovided on system 100 that initiates the time of flight anddifferential time of flight measurements. In the example, the triggersystem is an infrared or optical system coupled between wand 102 andsensor 101. For example, an optical transducer on wand 102 sends apulsed optical signal that initiates a measurement. The sensor 101 hasan optical transducer for detecting the pulsed signal. A measurementsequence is initiated when the pulsed optical signal is received. Ingeneral, the optical signal is received almost instantaneously whencompared to a simultaneously transmitted ultrasonic signal. The primarysensor 101 and wand 102 are low cost components that can be disposedafter surgery. The wand 102 is used to register points of interest withthe primary sensor 101. The points of interest can be on the bone or oncutting jigs 112 used during surgery. The system 100 reports alignmentof the bones or cutting jigs 112 by way of the wand 102 and the primarysensor 101. The system 100 can assist the surgeon in establishingalignment of the cutting jigs 112 and bones and evaluating surgicalprocess of alignment during and after surgery. The system 100 furtherincludes at least one mount within the surgical field. The mount retainsand holds the wand in a predetermined location during the surgery afterpoints of interest have been registered. In one embodiment, the sensor101, wand 102, and the mount are maintained within the surgical field.

As one example, alignment is achieved when the points of the femur head(A′), patella (B′) and ankle (C′) are positioned in a straight line. Aswill be explained ahead in more detail, the portable wireless alignmentsystem 100 intra-operatively assesses alignment of the femur and tibiabones during knee surgery. Certain aspects of alignment preparation canbe performed prior to surgery as will be discussed ahead. It can alsotransmit this information to associated wireless devices (e.g., laptop,cell phone, net book) and upload the information to a server on anetwork for example one connected to electronic medical or health carerecords. The system 100 assesses and reports in real-time the positionof these points, or other registered points, by way of a graphical userinterface on the communication device 104. In one embodiment,communication device 104 is a laptop computer. The communication device104 can be outside the sterile field but positioned such that a surgeonand surgical team can view the display while utilizing wirelessalignment system 100. It provides visual and auditory feedback relatedto alignment, such as audible acknowledgements, haptic sensation (e.g.,vibration, temperature), and graphical feedback (e.g., color-coded linedata).

Although shown as a coupled system, the wand 102 and the sensor 101 canoperate independently of the communication device 104. The customcontrol board (CC) and the DSP are integrated and scaled down onto thesensor 101 for local communication (e.g., close distance, paired) andprocessing. In this configuration the wand 102 and the sensor 101 alonecan assess and report alignment. As will be discussed ahead, the sensor101 includes a user interface that visually and audibly reportsalignment status. Afterward, the sensor 101 can be communicativelycoupled to the communication device 104 or server to download alignmentinformation or other captured data.

FIG. 1B depicts an exemplary embodiment of the primary sensor 101. Thesensor 101 can comprise two or more ultrasonic transducers 121-123 forthree-dimensional sensing. In one arrangement, each side of sensor 101can include a set of transducers 121-123. In the illustration, thetransducers 121-123 are mounted at predetermined positions or locationson a support structure. In one embodiment, the support structure is aprinted circuit board (PCB) 126. The predetermined positions oftransducers 121-123 are spaced to support the measurement of time offlight and differential time of flight signals by each sensor forlocation identification. In the example, the ultrasonic tranducers121-123 are mounted planar to the surface of the PCB 126 and co-planarto one another. The ultrasonic transducers can be MEMS microphones,ultrasonic receivers, ultrasonic transmitters or combination thereof. Asone example, each ultrasonic transducer can perform separate transmitand receive functions. One example of an ultrasonic sensor is disclosedin U.S. patent application Ser. No. 11/683,410 entitled “Method andDevice for Three-Dimensional Sensing” filed Mar. 7, 2007 the entirecontents of which are hereby incorporated by reference.

As described herein, additional transducer placed on a second side ofPCB 126 would be performed in a similar manner. The transducers 121-123can be covered with a material 128 or screen that is transmissive toultrasonic frequencies. The material 128 protects and prevents liquid orsolid matter generated during a surgery from affecting or modifying theperformance of transducers 121-123.

The sensor 101 can include an amplifier, a battery or power source, acommunications module (e.g., Radio Frequency modulator), anaccelerometer, and a controller. In one embodiment, the components aremounted to PCB 126 and operatively coupled to form a circuit withtransducers 121-123 to support three-dimensional sensing. The amplifierenhances the signal to noise of transmitted or received signals. Thecommunications module can include components (e.g., synchronous clocks,infrared, optical/acoustic pulse) for local signaling (sensor 101 towand 102) or network components (e.g., Bluetooth, ZigBee, Wi-Fi, GPSK,FSK) for wireless communications with the communication device 104(sensor 101 and wand 102 to a laptop 104 or other equipment) for sendingalignment data or information thereto. An optical or infrared transducercan be mounted on PCB 126. In one embodiment, the optical or infraredtransducer receives a trigger signal for initiating a measurement aswill be disclosed in more detail hereinbelow. The trigger signal issubstantially faster than an ultrasonic signal. In the example, thetrigger signal is launched from wand 102. The accelerometer identifiesaxial tilt (e.g., 3/6 axis) during motion and while stationary. Thecontroller is coupled to the transducers 121-123 and the accelerometerto receive data provided therefrom to determine a location of an objectin three-dimensional space within a surgical field. The controller caninclude a counter, a clock, and other analog or digital logic forcontrolling transmit and receive synchronization and sequencing of thesensor signals, accelerometer information, and other component data orstatus. The battery powers the respective circuit logic and components.

The controller can utilize computing technologies such as amicroprocessor (μP) and/or digital signal processor (DSP) withassociated storage memory 108 such a Flash, ROM, RAM, SRAM, DRAM orother like technologies for controlling operations of the aforementionedcomponents of the terminal device. The instructions may also reside,completely or at least partially, within other memory, and/or aprocessor during execution thereof by another processor or computersystem. An Input/Output port permits portable exchange of information ordata for example by way of Universal Serial Bus (USB). The electroniccircuitry of the controller can comprise one or more ApplicationSpecific Integrated Circuit (ASIC) chips, for example, specific to acore signal-processing algorithm. The controller can be an embeddedplatform running one or more modules of an operating system (OS). In onearrangement, the storage memory may store one or more sets ofinstructions (e.g., software) embodying any one or more of themethodologies or functions described herein. In the example, thecontroller is operatively coupled to an interface of sensor 101. Theuser interface alone or with laptop 104 can be used to visually,haptically, or audibly report a status.

The sensor 101 includes a mounting structure 120 for coupling to bone ora surgical cutting jig. As one example, the mechanism can be a magneticassembly with a fixed insert (e.g., square post head) to permittemporary detachment. The mounting structure 120 positions can positionsensor 101 in a reference position. In the illustration, sensor 101 iscoupled to the distal end of the femur. As another example, it can be amagnetic ball and joint socket with latched increments. In oneembodiment, the mounting structure 120 comprises a rod having first andsecond threaded ends. One threaded end couples to sensor 101 theremaining threaded end couples to a bone, cutting block, jig or otherstructure for supporting the device. A taper threaded region would beused to screw the mounting structure 120 into bone similar to anorthopedic screw. It is not limited to the embodiments disclosed hereinand others are attachment methods are contemplated.

FIG. 1C depicts an exemplary embodiment of the wand 102. The wand 102can include two or more transducers 131-133 for three-dimensionalposition detection and sensing. In the illustration, the transducers131-133 are mounted at predetermined positions or locations on wand 102.In one embodiment, the transducers are mounted on a printed circuitboard. The printed circuit board is placed within an enclosure thatallows wand 102 to be held in a hand. The wand 102 form factor will bedescribed in more detail hereinbelow. The predetermined positions oftransducers 131-133 are spaced to support the measurement of time offlight and differential time of flight signals by each transducer forlocation identification. In the example, the ultrasonic transducers121-123 are mounted planar to the surface of the PCB 126 and co-planarto one another. The ultrasonic transducers can be MEMS microphones,ultrasonic receivers, ultrasonic transmitters or combination thereof.

A tip 134 of the wand can be used to identify points of interest on themuscular-skeletal system, bone, or cutting jig 112. The ultrasonictransducers can be MEMS microphones, ultrasonic receivers, ultrasonictransmitters, or combination thereof. The ultrasonic transducers canperform separate transmit and receive operations. The wand 102 caninclude an attachment mechanism for coupling to bone or a surgicalcutting jig. One example of an ultrasonic sensing device is disclosed inU.S. patent application Ser. No. 11/683,416 filed Mar. 7, 2007 theentire contents of which are hereby incorporated by reference. It can beheld in hand, to identify via the wand tip, points of interest, orcoupled to an object to remain stationary. It can attach via a clip,clamp, magnetic base, slot, insert or other mechanism to a receivingobject (e.g., operating room overhead lights, operating room table,monitor stands, etc.)

The wand 102 can include an amplifier, a battery or power source, acommunications module (e.g., Radio Frequency modulator), anaccelerometer, and a controller. In one embodiment, the components areoperatively coupled to form a circuit with transducers 121-123 on theprinted circuit board to support three-dimensional sensing. Theamplifier enhances the signal to noise of transmitted or receivedsignals. The communications module can include components (e.g.,synchronous clocks, infrared, optical/acoustic pulse) for localsignaling (sensor 101 to wand 102) or network components (e.g.,Bluetooth, ZigBee, Wi-FI, GPSK, FSK) for wireless communications withthe communication device 104 (sensor 101 and wand 102 to a laptop 104 orother equipment) for sending alignment data or information thereto. Anoptical or infrared transducer can be mounted on the printed circuitboard or housing. In one embodiment, the optical or infrared transducersends the trigger signal for initiating a measurement as will bedisclosed in more detail hereinbelow. The accelerometer identifies 3 and6 axis tilt during motion and while stationary. The controller, like thesensor 101 controller, can include a counter, a clock, or other analogor digital logic for controlling transmit and receive synchronizationand sequencing of the sensor signals, accelerometer information, andother component data or status. The battery powers the respectivecircuit logic and components. The controller is coupled to thetransducers 131-133 and the accelerometer to support identification ofthe location of an object in three-dimensional space.

The wand 102 can include a touch sensitive tip 104 that registers pointsresponsive to a physical action, for example, touching the wand tip to abone or jig. The tip 104 extends from the wand housing. The touchsensitive tip 104 can comprise a mechanical accelerometer or actuatedspring assembly. In another arrangement, it includes a capacitive touchtip or electrostatic assembly. The wand 102 and sensor 101 may eachfurther include a haptic module and a user interface. As an example, thehaptic module may change (increase/decrease) vibration to signalimproper or proper alignment status. It may include a temperature moduleto change to warm or cold responsive to operational status. The userinterface can permit handheld operation and use (e.g., on/off/resetbutton) and provide visual feedback. As an example, one or more LEDlights can show alignment and direction (left/right/up/down). The sensor101 and the wand 102 can include material covering the transducers thatare transparent to sound (e.g., ultrasound) and light (e.g., infrared)yet impervious to biological material such as water, blood or tissue. Asan example, a clear plastic membrane can be stretched taught to vibrateunder resonance with a transmitted frequency and provide a hermeticseal. The battery supply of the wand 102 and sensor 101 can be chargedvia wireless energy charging (e.g., magnetic induction coils and supercapacitors).

The wand 102 can also be mounted or have a mount. In one embodiment, thewand 102 can include a mount to attach to a bone, cutting block, or jig.The mount can comprise a rod or fastener on or extending from thehousing of wand 102 that can screw into or attach to a structure. Amount can comprise a stand that retains and places wand 102 in a fixedposition. For example, a hanger can extend from a lighting system orceiling of the operating room within the sterile field. The wand 102 canbe placed on the hanger such that it remains in line of sight to sensor101 during the measurement and alignment process. Alternatively, a standor mount for wand 102 can be placed in the line of sight of sensor 101.The stand or mount retains wand 102 and can be fastened to a structuremaintain a fixed position.

FIG. 1D depicts an exemplary diagram of wireless wand to register pointsof interest with the system 100 (e.g., communication device 104). Duringregistration, the wand tip is touched to points of interest, forexample, the distal femur center, to register the location with thesensor 101. The communication device 104 can visually show the movementof the wand 102 in 3D with respect to the sensor 101. The wand 102 andthe sensor 101 can communicate via a local communications protocol (e.g.optical/ultrasonic pulsing) apart from the network communication (e.g.,Bluetooth, Wi-Fi) between the sensor 101 and the communication device104. In a master-slave configuration, the wand 102 serves as the slaveto inform the sensor 101 of the points of interest, and the sensor 101serves as the master for communication of the alignment information tothe communication device 104.

In one embodiment, the wand 102 and sensor 101 communicate locationinformation by way of ultrasonic pulsing and optical sequencing. Thewand 102 emits high frequency sound pulses (e.g., 40-120 KHz)transmitted by each of the respective transmitters that arrive at thereceivers of the sensor 101 at different times. The timing informationbetween each of the received pulses and the time length of sound travelcan be used to determine the location of the wand 102 relative to thesensor 101. Three sensors alone with this timing information can be usedto establish three-dimensional coordinates of the wand 102. Samplingintervals on the order of 160 to 200 samples (16-bit) per second pertransmitter are sufficient for real-time analysis and display. Inanother arrangement, only two sensors need be used on the wand toachieve a narrower physical profile for three-dimensional location andpositioning based on spherical propagation characteristics of soundwaves.

An example of voice recognition in an operating room or surgicalenvironment is disclosed hereinbelow. The exemplary embodiment utilizessystem 100 for alignment. A surgical field 148 is a region within theoperating room where the patient resides and where the surgery isperformed. The surgical field 148 is a sterile region that minimizespatient exposure when opened during surgery. One or more devices areused by the surgeon within the surgical field 148. In general, thedevices are active devices having at least one sensor for performing afunction or measuring a parameter. The active devices will further havecommunication circuitry to couple to an interface within the device orexternal for providing information or data.

An orthopedic surgical procedure is used as an example of applying voicerecognition. As shown, sensor 101 and wand 102 are devices used by thesurgeon to align two or more bones of the muscular-skeletal system. Morespecifically, the sensor 101 and wand 102 comprise an ultrasonicalignment system that is coupled to the patient within the surgicalfield. The devices can further include a prosthetic component having atleast one sensor for measuring a parameter. For example, the prostheticcomponent can be an insert for measuring a parameter such as a force,pressure, or load applied to an articular surface by themuscular-skeletal system. The system 100 further includes the portablecommunication device 104. In one embodiment, the communication device104 is a laptop computer having a display 150 with a GUI 152. Thecommunication device 104 is wirelessly coupled to the devices within thesurgical field 148 for receiving data from the sensors and displayingthe information on display 150. The display 150 can be outside of thesurgical field 148 but in view of the personnel in the surgical field148. In the alignment example, the display 150 shows patient alignmentand the measured parameter from the sensor in real-time. The measuredparameter can be a load magnitude and position of load on the articularsurface of the insert. The GUI 152 displays the quantitative data in amanner where the surgeon can consume alignment and the force, pressure,or load information simultaneously to rapidly apply the data to thejoint installation.

A transducer 142 is within the operating room for receiving audiosignals such as a vocal command. A digital signal processor 154 iscoupled to the transducer 142 and other components of system 100 such aswand 102, sensor 101, display 150, the insert, and communication device104. The audio signals received by transducer can be converted to adigital format for processing by the digital signal processor 154.Alternatively, the digital signal processor 154 can reside in portablecommunication device 104, sensor 101, or wand 102. In one embodiment, avocal command produces an operative change or action 146 in the coupledsystem between the one or more devices or the display 150 in theoperating room. For example, a voice command to “measure loading” caninitiate the insert to take the action 146 to measure the load on thearticular surface and display the position and magnitude of the load onthe display 150. Similarly, a voice command such as “magnify” couldresult in an action 146 to increase the size of figures on the display150. It should be noted that these are merely examples, many differenttypes of voice commands would be useful in surgical environment, whichwould vary depending on the application.

The digital signal processor 154 is coupled to voice recognitionsoftware 144. The voice recognition software 144 can assess audiosignals received from transducer 142. The voice recognition software 144can deliver the audio to an application specific software programlooking for specific words or phrases. As mentioned previously, thespecific words or phrases can be directed to the application orprocedure. In one embodiment, the voice recognition software 144 orother program identifies one or more words corresponding to an actionand provides a query to the identified words. The query can be a visualor auditory queue that requires a response. The query is a failsafe thatensures that the action being taken is the one that was requested viathe vocal command. The visual or auditory queue can be a restatement ofthe action as identified by voice recognition software 144. For example,a vocal response such as “yes” or “no” could be provided by the personwho initiated the vocal command. The response provided to the query willresult in the action being taken or the action terminated. In at leastone exemplary embodiment, one or more of the active devices in thesurgical field are disposable such that they are for a single use anddisposed of after the surgery.

A method of improving operating room efficiency is provided inaccordance with an exemplary embodiment. The steps disclosed herein canbe performed in any order or combination. An operating room in ahospital or clinic is a clean room environment that limits and preventsexposure to organisms or materials that could be harmful to a patientduring a surgical procedure. A surgical procedure is a verylabor-intensive process that currently utilizes a large number ofpersonnel. Moreover, the surgical procedure is performed within asurgical field of the operating room. The surgical field is a clean areawhere the patient, surgical personnel, and some equipment reside.Typically, movement of people, components, or material into and out ofthe surgical field is limited or restricted after the procedure hasstarted.

A surgeon has to perform many physical tasks during surgery. Often, thesurgeon is using both hands while concurrently directing other personnelduring the procedure. The field of view or the direct view of thesurgery is often not sufficient for the surgeon. Moreover, there aremany tools being introduced that include electronic or electromechanicaldevices to provide data. A display can be used to provide data frommeasurement devices as well as view of the surgery. The display can alsosequence through the steps of a surgical procedure as disclosed herein.In general, the display allows at a single glance a combination ofinformation, data, and the surgery.

In the disclosed method, information related to a surgical procedure isdisplayed on a display in the operating room in a first step. Examplesof information can be measured data, steps of a procedure, visual aids,or live video of the procedure. The information is presented in a GUIthat enhances the efficiency and accuracy in which the procedure can beperformed. In a second step, a command is vocalized to initiate anaction. The action can be related to the display, devices takingmeasurements, or the procedure. Initiating the action results in achange to the device in which the action is directed. A transducerwithin the operating room receives the audio signal. The audio signalcan be converted to a digital signal and further processed to enhancerecognition. In one embodiment, the audio signal is processed by adigital signal processor (DSP) running voice recognition software. In athird step, the command is identified using the voice recognitionsoftware. For example, an action could be to select a page on thedisplay, change an order of the images, zoom-in, zoom-out, to name but afew of the commands that would aid the surgeon while performing thesurgery. Similarly, actions such as enable, disable, measure, andcalibrate can control active devices used in the procedure. Althoughsimple actions are provided as examples more sophisticated operationsrequiring more complex phrasing and software interpretation can beimplemented.

Typically, voice command actions are used in a manner to maintainpatient safety. In one embodiment, recognized words or phrases are notimplemented directly. In a fourth step, a query is provided to theidentified command. For example, the query can be visual, audible, orboth. On query would be to show the identified action on the display orrecite it audibly. In a fifth step, a response to the query is providedto initiate or terminate the action. For example, an audible responsesuch as yes or no could be provided to answer the query. A “yes”response to the query would be received and identified by the voicerecognition software. The affirmative response would send a signal tothe appropriate device to initiate the action. Conversely, a “no”response received and identified by the voice recognition software couldterminate the action. Further measures could be taken to ensure acorrect response such as voice identification of the person initiatingthe action to prevent other audio input from triggering the action.

In a sixth step, one or more sensors are coupled to the patient. The oneor more sensors measure a parameter corresponding to the surgery.Measurements such as pH, temperature, viscosity, electrical activity,load, density, pressure, force, distance, and alignment are examples ofparameters that can be monitored during surgery. In a seventh step, thequantitative measurements from the one or more sensors are displayed inreal-time on the display. As mentioned previously, the data can beprovided in a format that aids the surgeon during the procedure. Forexample, bone alignment can be shown with bones being displayed on thedisplay in relation to one another as the surgeon sees on the operatingtable. The bone and bone angles would change on the display in real-timeas they are moved.

The steps of the procedure can be supported on the display. In an eighthstep, the steps of the surgical procedure can be provided in sequence onthe display. The measured parameters corresponding to the patient or thesurgery can be provided on the display that supports the step of theprocedure being performed. During the step, at least one voice commandis initiated to generate an action related to the display or sensors. Anexample would be to register a point or location on the patient orturning to the next step in the procedure after the prior step wascompleted.

In a ninth step, adjustments are made during the surgical procedure thatchange the readings measured by the one or more sensors. The sensorsreport in real-time which is displayed on the display. The surgeon canbenefit from seeing changes in quantitative data as modifications arebeing made. Furthermore, the surgeon can make fine adjustments to aspecific parameter range while viewing the display or interfaces on themeasurement devices. In a tenth step, the measurements can be recorded.In one embodiment, the surgeon can determine by voice command when dataor a measurement is stored. In an eleventh step, the one or more sensorsare disposed of after the surgical procedure. In the example, sensorsare in contact with the patient. The devices having the sensors aredesigned for a single use and are disposed of along with any biologicalmatter.

FIG. 1E depicts an exemplary diagram for local communication and pointregistration between the wand 102 and the sensor 101. It illustratestransmit timing, sequence and pattern information using a combination ofultrasonic and optical signal processing according to one embodiment.The wand 102 simultaneously transmits a light signal (e.g., infraredpulse) with the ultrasonic pulse to signify sequence start of eachultrasonic pulse. The light signal is received at the sensor 101 totrigger timing of the received sound signal (e.g., ultrasonic pulse).The sensor 101 determines the time of flight of the ultrasonic pulseresponsive to receiving the light signal, including any compensatorytime information. For instance, a clock counts the elapsed time or issequenced to an oscillator circuit.

The transmit characteristics of the ultrasonic pulse can change as afunction of time, frequency and intensity as shown in FIG. 1E. Oneexample of an ultrasonic transducer for pulsing is presented in U.S.Pat. No. 7,414,705 entitled “Method and System for Range Measurement”,the entire contents of which are hereby incorporated by reference. Thepulse duration, harmonic frequency content, frequency profilecharacteristics, phase and amplitude can all be adaptively changedduring alignment measurement to maximize signal to noise ratio, distancemeasurement, and environmental conditions (e.g., temperature, drift,etc.). As one example, the microphone can assess noise floors and conveythis information to a processor to adjust the ultrasonic pulsecharacteristics. As one example, each transmit sensor on the wand 102can individually adjust it's transmit amplitude and frequency tomitigate interference and/or generate selective interference patterns.The sensor 101 can process the interference patterns via patterndetection, look up tables, spectral distortion measures, or statisticalsignal processing approaches to refine position estimates (e.g., <x,y,z>location). One example of an ultrasonic sensor is disclosed in U.S. Pat.No. 7,725,288 the entire contents of which are hereby incorporated byreference. The ultrasonic sensors can transmit pulse shaped waveforms inaccordance with physical characteristics of a customized transducer forconstructing and shaping waveforms

Another embodiment incorporates synchronized clocks on both the wand 102and sensor 101. A light pulse can initiate or reset synchronization. Thesynchronization is timed with the ultrasonic travel time and estimatedwand 102 locations. As yet another example, Radio Frequency (RF) pulsingcan be used to trigger onset timing of an ultrasonic pulse. The RF pulsecan be transmitted with the ultrasonic pulse to identify the start timefor measuring the ultrasonic pulse travel time. The sensor 101 and thewand 102 can be calibrated prior to use to ensure propersynchronization. In one configuration, bringing the wand 102 in closeproximity to the sensor 101 can perform a calibration function, resetsynchronization, or adjust another user function. One example of anultrasonic sensing for such configuration is presented in U.S. patentapplication Ser. No. 11/562,404 entitled “Method and System for ObjectControl” filed Nov. 21, 2006, the entire contents of which are herebyincorporated by reference.

FIG. 1F depicts an exemplary method for assisted guidance navigation byway of the portable wireless alignment system 100. The method can bepracticed with more or less than the number of steps shown and is notlimited to the order shown. Completion of the method steps duringsurgical operation is on the order of 5-7 minutes.

The method can begin at step A in which the surgeon affixes the primarysensor 101 to the distal end of femur or a cutting jig 112 (see FIG. 1).As an example of affixing, a screw post 124 can include a detachablemagnetic assembly to temporarily couple the sensor 101 to the bone orjig 112. At step B, the surgeon uses the wireless wand to identify thecenter of the distal end of femur. The surgeon touches the location(s)corresponding to the femur extension center and/or flexion center. Thesurgeon depresses a user interface component (e.g., touchpad, button,switch, etc.) on the wand 102 or speaks a voice command to register thepoint. The location information can be visually displayed on thecommunication device 104, for example, rendered in three-dimensions (3D)with the bone and/or cutting jig.

Upon affixing the primary sensor 101 and registering the femur center,the surgeon then places the wand at a stationary location with aline-of-sight to the primary sensor 101 at step C. As one example, thewand 102 is coupled to an extending base on an overhead operating lightwithin the operating room. Placing the wand 102 above the operatingspace provides a clear signal path to other sensors or devices whilebeing out of the surgical work area. At step D, the surgeon rotates thepatient's femur for 10-15 seconds to identify the hip center (femurhead). The sensor 101 processes the time of flight (TOF) and delta(dTOF) information to identify the 3D location of the stationary wand102 with respect to the rotating (moving) sensor 101. It can furtherincorporate optical pattern information for example with navigationsystems using infrared components. As one example, the processor withinthe sensor 101 can perform a least means square (LMS) operation from thespherical surface points to estimate a radius and center of the femurmovement; to correspond to the femur head. A general likelihood testmetric or adaptive filter can further resolve the femur head center.Receive data (e.g., acoustic waveform, zero crossings, peaks, etc.) canbe buffered into memory and selectively indexed according to closestdistance or distortion metrics. One example of a memory configuration ispresented in U.S. patent application Ser. No. 12/146,445 entitled“Method and Device for Enhancing Accuracy in Ultrasonic RangeMeasurement” filed Jun. 26, 2008, the entire contents of which arehereby incorporated by reference.

The location information is incorporated into the cutting jig forsurgery at step E. Computer Aided Topography (CAT) scans and MagneticImage Resonance (MRI) scans can be further employed to resolve the femurhead location in conjunction with the sensor 101 information.Three-dimensional (3D) CAT and MRI scans loaded into the communicationdevice 104 for example prior to surgery during another registrationprocess can be scanned in view of the sensor 101 information to confirmthe femur head location. Registration can be performed to correlate theposition of the wand in the surgical field and the correspondinglocation on the CT or MRI images. Femur neck geometries (e.g., angle,vector, magnitude) are also incorporated when projecting sphericalbest-fit techniques to the projected rotation data.

As one example, FIG. 3 briefly depicts an exemplary embodiment where aportable hand-held ultrasound probe or scanner can be used to identifythe femur head center. This process can be performed just prior tosurgery during patient preparation for further femur head confirmation.The hand-held probe is operatively coupled to the communication device104 to show the ultrasound scan. The surgeon can scan the hip area andthen point via a touchless finger gesture or touch-screen to identifyand register the femur head. The system 100 incorporates the visuallyidentified femur head location with the spatial femur head positionderived from the sensor 101 and wand 102 arrangement. One example of anultrasonic control is presented in U.S. patent application Ser. No.11/566,156 entitled “Method and System for Activating a TouchlessControl”, the entire contents of which are hereby incorporated byreference.

Returning back to the method of FIG. 1F, at step F, the surgeon uses thewand to identify the ankle center and thereafter the proximal end oftibia center. The left side of the ankle then the right side can bebriefly taped to register the ankle contour. The sensor 101 can thenestimate the ankle center through a weighted average (e.g., 0.6 distancefactor). This registers the distal tibia point of interest (anklecenter) with the sensor 101. The surgeon then at step G, affixes thewand 102 to the proximal end of tibia center or to a tibial cutting jig112 (see FIG. 1). In this position the wand 102 is stationary and indirect communication with the sensor 101. The surgeon can then adjustthe tibial cutting jig or the tibia to achieve proper alignment. Thesystem 100 reports alignment of femur head, primary sensor and wand atstep H.

FIG. 1G shows a generic 3D Graphical User Interface (GUI) of alignmentbetween three points representing the femur head, patella (knee cap) andankle center. The points move in real time with the movement of the legbones or attached jigs with sensors. Although shown on the display ofthe communication device 104, it can also be presented on the userinterface of the sensor 101 itself, for example, via 3 or more LEDlights. Alignment is achieved when the end points are overlaid with oneanother as in the left subplot and are in alignment as shown in theright subplot. Alignment precision is on the order of millimeters. In ageneral configuration, wand 102 is stationary and approximately 20″overhead the hip center, Sensor 101 is at the knee joint andapproximately 18″ from the hip center, and wand 102 when placed at theankle center is approximately 19″ from S2. The workflow takes about 5-7minutes from start to generate alignment results.

The alignment tool supports 3D rendering in real-time. It shows multipleviews and reports an alignment angle as the sensors are moved inphysical space. It shows a i) main perspective view, ii) top view, andiii) side view. Mouse controls permits zoom, scaling and rotation oneach separate view. The display can be further customized for userinterface controls to render the views, communicate with the hardware,and other UI functionality. The alignment angle can be modified toreport valgus and varus deviations.

Disclosed hereinbelow are low-level steps of an orthopedic operatingroom surgical workflow in accordance with an exemplary embodiment. Inthe example, reference to FIGS. 1A-1D, FIG. 4A, FIG. 7, and FIG. 8 willbe made. The method can be practiced with more or less than the numberof steps shown and is not limited to the order shown. In a first step,information and patient data is provided to a first GUI page forcommencing the workflow. It can be input to the remote system 104, whichin the present embodiment hosts the GUI 107. In one embodiment, GUI 107hosts the customized workflow for the total knee replacement procedure.An example of a navigated workflow is disclosed in U.S. patentapplication Ser. No. 12/900,878, the entire contents of which are herebyincorporated by reference. The patient name and surgery information canbe entered into the GUI 107. It also documents a time in and time out toconfirm the patient with the procedure. A reader can also be coupled tosystem 104 for scanning information on the prosthetic components usedprior to installation.

In a second step, the sterilized components (sensorized tools) of thenavigation system 100 are opened, activated and calibrated. Thisincludes: sensor 101, a mounted wand (not shown), and hand-held wand 102(hereinafter system components). The calibration is a short procedurewhere the system components are validated for user requirement accuracy.In a third step, the system components broadcast their activation. TheGUI 107 indicates (e.g., visual, auditory, and/or haptic) that thesystem components are on and operational according to specification.

After the patient is prepped for surgery the GUI 107 transitions to afemur registration page with information to provide visual guidance. Theknee is opened with a longitudinal incision to expose the knee joint.Retractors are applied to protect soft tissue. In a fourth step, a femurpin can be placed in the distal femur. The sensor 101 is mounted to thefemur pin (in or out of incision). As an example of affixing, a screwpost can include a detachable magnetic assembly to temporarily couplethe sensor 101 to the bone. Other affixing means are hereincontemplated. The printed circuit board 126 is angled medially such thatthe sensor 101 is line-of-sight to the mounted wand.

In the example, the GUI 107 transitions to a tibia registration page. Ina fifth step, a tibial pin can be pinned in the proximal tibia or midwayon the tibia. The mounted wand is mounted to the tibial pin to beline-of-sight with the sensor 101. Similar mounting mechanisms can beincluded to ensure a rigid attachment of the mounted wand to the tibialpin.

In a sixth step, the wand 102 is temporarily mounted to a stationarystand and angled towards the sensor 101. The stationary stand can beaffixed to a table, equipment, or overhead within the sterile field.Wand 102 serves as a reference location for the sensor 101 when thesensor 101 is moving, as will be disclosed ahead. The wand 102 can beplaced within close proximity of the sensor 101, for example, within 2meters, and out of the way of the mechanics of the procedure.

In a seventh step, the tibia is moved through a first range of motion(ROM1) from extension (straight leg) to flexion (knee bent ˜90 degrees)to ensure the sensor 101 and the mounted wand remain sufficiently inline-of-sight; approximately −60 to 60 degrees face-to-face incidentangles. The GUI 107 confirms local line of sight between the sensor 101and the mounted wand during the step. The GUI 107 can provide sensoryfeedback to visually or audibly indicate line-of-site conditions, forexample, turning red or green accordingly or specifying vocally that thecomponents are line of sight.

In an eighth step, the GUI 107 transitions to a femoral Identification(ID) page. It instructs the surgeon to place the hip in flexion andapply gentle femoral rotation. The rotation is shown on the upperportion of the display in FIG. 7. This motion is applied in a ninth stepto allow the sensor 101 to identify the femoral head (e.g., hip joint).One example of determining the femur head center is disclosed in U.S.patent application Ser. No. 12/900,955 filed Oct. 8, 2010 entitled--“Orthopedic Method and System for Mapping an Anatomical Pivot Point,the entire contents of which are included by reference in entirety.Another is based on pivot point determination in U.S. Pat. No.7,788,607, the entire contents of which are hereby incorporated byreference. The GUI 107 visually confirms this second range of motion(ROM) in the step, for example, by indicating a green status forline-of-sight in a tenth step. Typically, line of sight is approximately±60 degrees conical to maintain user requirement precision, but canapproach up to ±90 degrees for some applications. It indicates a redstatus when the ROM is outside the line-of-sight. In an eleventh step,GUI 107 informs the surgeon when the femoral head is registered andlocated within accuracy—it shows data collection, timestamp, and checkpoints. The femur head establishes a first point for mechanical axisalignment of the leg.

Once the GUI 107 confirms femur head identification, the wand 102 isremoved from the stationary (overhead) stand in a twelfth step. It isthereafter used to register the anatomical landmarks during the workflowprocedure. In a thirteenth step, the GUI 107 instructs the surgeon toregister distal femoral center with wand tip 134. The GUI 107 alsoindicates visually or audibly if the wand 102 falls out of theline-of-sight and/or requires surgeon to re-register landmarks. In theexample, the locations of the lowest points on distal femoral condyles(medial and lateral), epicondyles, anterior cortex of distal femur, andposterior femoral condyles (PFC) (medial and lateral) are registered bywand 102.

In a fourteenth step, the GUI 107 instructs the surgeon to use the wand102 to register the tibial landmarks such as the center of tibia (baseof ACL) and the deepest points on proximal medial and lateral tibialplateau. In a fifteenth step, the GUI 107 instructs the surgeon to usethe wand 102 to register landmarks of the ankle such as the medialmalleolus and the lateral malleolus. During the registration disclosedabove, the GUI 107 visually shows the registered points on the displayin 3D, but is not limited to only the registration of these points. Italso displays the desired mechanical axis of the leg for the leg inextension case (see FIG. 1, line ABC).

In a sixteenth step, dynamic knee data and leg information is capturedrelated to the patient's current leg alignment and knee flexion. Thisinformation is recorded and reported. The knee flexion is specified byan angle indicating the amount of hyperextension through full bending ofthe knee (flexion). This angle can be between −10 to +120 degreesdepending on the patient's condition. The GUI 107 instructs the surgeonto place the knee in extension and hold the leg steady to register theextension angle and mechanical axis. The knee is then moved through afull range of motion while the sensor 101 collects flexion data throughminimum to maximum range. The GUI 107 tracks and reports the femur andtibia during the movement through the range of motion.

In a seventeenth step, the GUI 107 transitions to a femoral resectionand instrumented cutting jig page. The knee is placed in flexion. Duringthis step, the mounted wand may be temporarily removed from the tibialpin if it is in the way, but remounted in a later step ahead. The wand102 is then mounted to a femoral cutting jig. Referring to FIG. 8, thewand 102 is shown in more detail. The illustration shows wand 102coupled to a mount 802. In one embodiment, mount 802 is a cutting blockor cutting jig. For example, mount 802 is a cutting block that couplesto a distal end of the femur. Mount 802 is aligned by the alignmentprocess to the femur for guiding a saw to generate bone cuts that have arelationship to the mechanical axis of the leg. This permits the sensor101 to track translation and orientation of the cutting jig component(e.g. mount 802) for establishing femoral cutting angles specific to aprosthetic component in an eighteenth step. During navigation of thecutting jig, the GUI 107 displays the distal femur and registeredfemoral features, tracking of the femoral cutting jig, cutting planeswith depth of cut to each registered distal condyles, flexion/extensionangle of cutting plane relative to femoral mechanical axis, andvarus-valgus angle of cutting plane relative to femoral mechanical axis.The mount 802 includes a feature for receiving and retaining tip 134 ofwand 102. The feature can be a compression fit, threaded for coupling totip 134, or magnetic to name but a few retaining methods contemplated.Similar approaches can be used for mount 802 attached in other localeswithin the surgical field to position wand 102 in fixed line of sightposition. A feature 802 can be used to couple wand 102 to a lightfixture, overhead, or to an attaching feature within the surgical fieldthat is out of the way but in communication to the measurement system.

Wand 102 has a body 802 that allows a user to easily hold the device inthe hand for registering points of interest. A control 804 is accessibleto the hand or fingers for controlling operation of the device. In oneembodiment, control 804 can be a switch or a scrolling device withswitching capability. Control 804 can be used in conjunction with aninterface 806 on the body 804 of wand 102. A transducer 810 can receivevocal or audible signals. The vocal signals are coupled to a digitalsignal processor of the measurement system having voice recognitionsoftware. Recognized terms or phrases are then converted into actions bya software program that can be performed by the measurement system. Oneexample of voice recognition in a navigated workflow with the sensorizedtools is disclosed in U.S. patent application Ser. No. 12/099,662entitled “Method and Device for Virtual Navigation and Voice Processing”filed Apr. 8, 2008 and claiming priority to Provisional PatentApplication 60/911,082 filed Apr. 11, 2007; the entire contents of whichare hereby incorporated by reference. The wand 102, sensor 101, remotemodule 104 and the mounted wand can be responsive to the vocal commands.Furthermore, each active component of the system can have a transducerfor receiving vocal commands and communication circuitry to wirelesslycouple to the digital signal processor. Ultrasonic transducers 131-133extend from the body 802 of wand 102. The extensions on wand 802 placeultrasonic transducers 131-133 the predetermined distance apart fromeach other to support three-dimensional location identification. Anotherexample of voice recognition in a navigated workflow is disclosed inU.S. patent application Ser. No. 12/723,486 entitled “Sterile NetworkedInterface for Medical Systems” filed Mar. 12, 2010 and claiming priorityto Provisional Patent Application 61/159,793 filed Mar. 12, 2009; theentire contents of which are hereby incorporated by reference.

In an nineteenth step, the femoral cutting jig is positioned andnavigated in view of the GUI 107 and pinned securely to the distal femurfor the desired cutting plane. The distal end of the femur is then cut.The femoral cutting jig is then unpinned and placed bottom flat surfaceon the cut distal femoral surface to verify cut accuracy; that is, it islaid against the cut. The GUI 107 reports distal femoral cut accuracybased on the positioning of the wand 102 mounted to the cutting jig.

The GUI 107 then transitions to the tibial resection and instrumentedcutting jig page. The wand 102 is then removed from the femoral cuttingjig and attached to a tibial cutting jig in a twentieth step. Referringto FIG. 4A, additional sensors can be provided to make the process moreefficient. Sensor 204 can be attached to the tibial cutting jig forlocating a point in three-dimensional space. Sensor 203 can be anadditional wand used to register points. As shown and disclosed hereinadditional sensors can be used during the knee procedure if desired.Referring back to FIG. 1A, during this time, the mounted wand may beremounted to the tibial pin if it was previously removed. In atwenty-first step, the repositioning of wand 102 permits the sensor 101to track translation and orientation of the tibial cutting jig forestablishing tibial cutting angles to make tibial cuts. In oneembodiment, the GUI 107 displays tibia and registered tibial features,the tibial cutting jig, the cutting plane with depth of cut to lowestpoints on medial and lateral tibial plateau, varus-valgus angle ofcutting plane relative to the tibial mechanical axis, andanterior/posterior slope relative to the tibial mechanical axis.

In a twenty-second step, the tibial cutting jig is positioned andnavigated in view of the GUI 107 and pinned securely to the tibia forthe desired cutting plane. The proximal end of the tibia is then cut.Bony or meniscal remnants are removed from the cut area. The tibialcutting jig is then unpinned and placed bottom flat surface on the cutproximal tibial surface to verify cut accuracy. The GUI 107 reportsproximal tibial cut accuracy based on the positioning of the wand 102mounted on the tibial cutting jig.

In a twenty-third step, upon completion of the tibial cut, the knee isextended with an extension block to assess extension gap and confirm gapresection. The extension gap is a volumetric void between the distalfemur end and the proximal tibia end; a portion of the void was createddue to the cutting of the femur bone end and the tibial bone end, whichhad partially occupied that region prior to cutting. The GUI 107displays the measured gap distances and varus/valgus alignment in atwenty-fourth step. These measurements can be verified by the navigationsystem in addition to the extension block. The gap distance is afunction of knee flexion and indicates the flexibility and strength ofthe medial and lateral knee tendons. The gap distance in extension (legstraight) can differ from the gap distance in flexion (leg bent) by afew millimeters. It also provides an indication of a permitted level ofsoft tissue release for achieving proper balance and alignment, which isperformed in a twenty-eighth step. The gap distance is also assessed inorder to determine appropriate chamfer cutting angles on the distalfemur and proximal tibia and trial insert sizes.

The GUI 107 then transitions to a femoral Anterior-Posterior (AP) andchamfer cuts page. The knee is placed in flexion. In a twenty-sixthstep, the wand 102 is mounted to a 4-in-1 cutting block, which is asophisticated jig that provides four different cutting angles in oneblock. The AP position and rotary position of the 4-in-1 cutting blockis then defined in view of the GUI 107. The GUI 107 shows the locationand orientation of the (sensorized) 4-in-1 block relative to the cuttingplanes and registered anatomical features. In a twenty-seventh step, the4-in-1 block is positioned and navigated in view of the GUI 107 andpinned securely for the desired cutting plane. The AP cut is made andthereafter the chamfer cuts are made on the distal femur end in thetwenty-eighth step. Upon making the first series of cuts, a tensioningdevice is then applied off the tibia in a twenty-ninth step to distractthe knee joint to cause the ligaments to rotate the femur until it isparallel to the cut tibial plateau (ligament tensioning technique). The4-in-1 block is then positioned and navigated in view of the GUI 107with the incorporated AP positioning. The 4-in-1 block is pinnedsecurely for the desired cutting plane and the final AP and chamfer cutsin a thirtieth step.

The GUI 107 then transitions to an insert trialing page, which guidesthe surgeon through selecting trial inserts. In a thirty-first step, thefemoral and tibial implant trials with tibial insert trial are inserted.During this procedure, a load sensing insert device can also be embeddedwithin the tibial trial insert to assess balance. Thus, multipleparameters of the muscular-skeletal system are being measured providingthe surgeon with quantitative data to support subjective feel duringsurgery. An exemplary relationship is illustrated among such componentsthat comprise a prosthetic knee implant: the sensing module 911, thefemoral prosthetic component 914, tibial prosthetic (tray or plate)component 916, and the tibial insert dock 912 in FIG. 9. The loadsensing insert device 911 provides a concave articular surface againstwhich the outer condylar articulating surface of the femoral prostheticcomponent 914 rides relative to the tibia prosthetic component 916.Examples of a load sensing insert sensing module are described inORTHO-01US, U.S. patent application Ser. No. 12/825,638 entitled “SYSTEMAND METHOD FOR ORTHOPEDIC LOAD SENSING INSERT DEVICE”, ORTHO-07US, U.S.patent application Ser. No. 12/825,724 entitled “WIRELESS SENSING MODULEFOR SENSING A PARAMETER OF THE MUSCULAR-SKELETAL SYSTEM”, ORTHO-10US,U.S. patent application Ser. No. 12/825,770 entitled “INTEGRATED SENSORFOR MEDICAL APPLICATIONS”, ORTHO-27US, U.S. patent application Ser. No.12/826,329 entitled “SENSING MODULE FOR ORTHOPEDIC LOAD SENSING INSERTDEVICE” all filed Jun. 29, 2010; the entire contents of each which arehereby incorporated by reference herein. In such a configuration, thenavigation system 100 reports combined balance and alignment informationby way of the GUI 107.

Referring back to the operative steps of the knee example, the knee isremoved through a third range of motion to assess implant stability,slipping and proper fit in a thirty-second step. During the third rangeof motion, the GUI 107 displays the knee with extension angle andmechanical axis in a thirty-third step. It also displays combinedbalance and alignment information when the sensing module 911 isincluded therein. The GUI 107 reports knee flexion, balance andalignment while the knee is moved through maximal flexion throughextension to hyperextension as permitted. During the third range ofmotion, the knee may be subluxed posteriorally in flexion in view of theGUI 107 to define any posterior instability. In a thirty-fourth step,the patella is cut and trialed. The femur bone and tibia are thenprepped for implant and cemented in a thirty-fifth step and the finalpoly is inserted. The knee is moved through a final range of motion inview of the GUI 107 displaying the extension angle and mechanical axisto validate balance and alignment in a thirty-sixth step.

FIG. 2A depicts an exemplary GUI that visually identifies a directionand distance of the sensor configuration to show tracking performance ofone sensor as it is moved in 3D space as in step B.

FIG. 2B depicts an exemplary GUI that visually identifies a location ofthe femur head from rotational movement of the femur as in step D.

FIG. 2C depicts an exemplary GUI that visually shows mapping of legmovement in physical space to the display and reports range of motionand alignment as in step H.

FIG. 2D shows a three-dimensional (3D) software Graphical User Interface(GUI) display. The alignment tool plots the positional location (greendots) of the TX relative to the RX (<0,0,0> origin of white stick)during real-time movement of the femur. The physical configurationproduces a 3D loci of points on a spherical surface that is used toidentify the centroid (e.g., pivot point; yellow dot). Five hundred(500) surface points or less can be used to calculate the centroid (10seconds of moving the femur).

FIG. 2E shows a three-dimensional (3D) software Graphical User Interface(GUI) display. Yellow line shows femoral axis; purple line shows tibialaxis; and green line shows femoral head center point with ankle centerpoint. Alignment is achieved at 180° (or 0° valgus/varus) when greenline overlays purple line in top and side views. Perspective viewpermits viewing of femur and tibia center. The displayed bones move in3D virtual space as the femur and tibia are moved in physical space.

FIG. 4A depicts another exemplary embodiment of a portable assistedguidance system 200 similar in function to the sensor-wand configurationof FIG. 1A. The system 200 comprises a group of sensors 201-204communicatively coupled to an acquisition system 205 by way of a wiredor wireless connection. The group of sensors 201-204 can be individuallyhermetically sealed for clean room conditions during surgery. Theacquisition system 205 can comprise a custom control board (CC) a DSPboard and a laptop, although, in other embodiments, the CC and DSP canoperate internally from a customized laptop using electronic processingresources therein (e.g., processor, memory, converters, etc.)

The system 200 is portable in that it can be managed by the laptop andthe sensors 201-204, which are self-contained and disposable. As oneexample, each sensor 201-204 can be individually packaged prior tosurgery and specific to the surgical procedure performed. Each sensorcan include one or more ultrasonic transducers that in addition to beingused for alignment can provide an embedded bar code. The acquisitionsystem 205 by way of each individual and labeled sensor can performautomatic data logging and asset tracking prior to and during surgery;information, which can be, relayed to a database administration systemor healthcare records.

Each sensor 201-204 can be entirely sealed in a disposable plasticpackage. An adhesive can affix it to the patient prior to surgery. Asensor can also comprise one or more sensing elements (e.g., MEMSultrasonic transducer, optical element, laser, camera) for permittingthree-dimensional tracking, for example by way, of sound localization,optical line of sight, optical pattern recognition, or any combinationthereof. The sensor can include other processing components in additionto just the sensing elements (e.g., acoustic transducers, opticalelements, infra-red elements, etc.).

FIG. 4B depicts a block diagram of an exemplary sensor 201-204 suitablefor use in the portable assisted guidance system 200 of FIG. 4A. Withrespect to FIG. 4A, each sensor 201-204 in the system 200 may containmore or less than the number of components shown depending on function.For instance, Sensor 201 and Sensor 203 may contain only an ultrasonicsensor with a transceiver for strictly disposable use. Sensors 202 and204 may contain all the components shown in FIG. 4B. The sensor can bewaterproof and shock absorbent.

In a wireless communications setting, the transceiver 102 can utilizecommon technologies to support singly or in combination any number ofwireless access technologies including without limitation, FM modulation(FSK, PSK, GPSK, BSK, etc.), Bluetooth™ 802.15, Wireless Fidelity(Wi-Fi) 802.11a/b/g/n, Worldwide Internet access 802.16 (WiMAX), UltraWide Band (UWB), software defined radio (SDR), and cellular accesstechnologies such as CDMA-1X, W-CDMA/HSDPA, GSM/GPRS, TDMA/EDGE, andEVDO. SDR can be utilized for accessing a public or privatecommunication spectrum according to any number of communicationprotocols that can be dynamically downloaded over-the-air to theterminal device. It should be noted also that next generation wirelessaccess technologies can be applied to the present disclosure.

The controller 106 can utilize computing technologies such as amicroprocessor (μP) and/or digital signal processor (DSP) withassociated storage memory 108 such a Flash, ROM, RAM, SRAM, DRAM orother like technologies for controlling operations of the aforementionedcomponents of the terminal device. The instructions may also reside,completely or at least partially, within other memory, and/or aprocessor during execution thereof by another processor or computersystem. The Input/Output 104 permits portable exchange of information ordata for example by way of Universal Serial Bus (USB). The electroniccircuitry of the controller 106 can comprise one or more ApplicationSpecific Integrated Circuit (ASIC) chips, for example, specific to acore signal processing algorithm. The controller 206 can be an embeddedplatform running an operating system (OS), such as windows mobile orAndroid. In one arrangement, the storage memory may store one or moresets of instructions (e.g., software) embodying any one or more of themethodologies or functions described herein.

The sensor unit 112 can comprise ultrasonic sensors, MEMS sensors,microphones or any combination thereof. As one example, the sensor unit112 can comprise both narrowband and broadband ultrasound source andreceivers (40 to 200 KHz) capable of localization of received signals bytriangulation through time of flight (TOF) and differential TOF (dTOF)measurements; at least 3 broadband ultrasound receivers and 1 broadbanddirected source with spread of approximately 120 degree conical sectioncan be used.

The accelerometer 114 measures the acceleration it experiences relativeto gravity or motion. Single- and multi-axis MEMS models detectmagnitude and direction of the acceleration as a vector quantity, andcan be used to sense orientation, vibration and shock. By way of theaccelerometer 114 sensor 130 can determine orientation or movementrelative to one another.

The optical module 116 can detect and transmit visible light andinfrared light. It can also record images as either a still photo ormoving images. The optical module 116 can include optical sensors, lightsensors, CCD, CMOS or MEMS elements to capture the light of the visiblespectrum or use with other portions of the electromagnetic spectrum. Thecaptured light data can be saved to internal memory or communicatedthere from by way of the transceiver 102.

The User Interface 118 can include one or more visual elements, such asa LED to indicate operation (e.g., green, yellow, red), or one or moreinteractive elements, such as a softkey or touchpad to initiate aprocess (e.g., on, off).

The Haptic module 119 can include a motor and a mechanical integritydevice (accelerometer) for shock and vibration.

The power supply 120 can utilize common power management technologiessuch as replaceable batteries, supply regulation technologies, andcharging system technologies for supplying energy to the components ofthe terminal device and to facilitate portable applications. The powersupply can include ultra-capacitors for energy storage. In clinicalsettings, the power supply 214 can be modified to extract energy from acommon wall outlet for charging to supply DC power to the components ofthe terminal device 106. The charging can also be performed by inductivemeans while the sensor device remains in sanitary packaging.

Drive and receive electronics can be contained on a PCB inside thesensor and contain analog interface circuitry, A/D and D/A circuits andDSP or microprocessor. Power can be delivered via wireless magneticinduction or USB cable to main processor module. The sensor can includea super capacitor for smooth energy delivery and filtering of transientsfrom burst operation.

The processor can include a unique hardware key for registering use ofthe device and for medical reporting. To ensure single use, the systemcan connect to a server for registration to receive encrypted key. Theservice center can send a program with the embedded key to ensure propermedical use. The key information can be hidden and retrieved byauthorized persons. The sensors 101 can deactivate after such use orafter a pre-specified amount of time.

FIG. 4C depicts an exemplary method for femur head identification by wayof the system 200. The method can be practiced with more or less thanthe number of steps shown and is not limited to the order shown.

The method can begin at step 402 in which Surgeon opens knee to performknee replacement operation. At step 404, the surgical team unpacks theknee alignment solution from packaging and turns on the sensors. At step406, the primary sensor establishes a wireless communication link with aPC running software that supports knee alignment solution. The Surgeoninserts a screw post into the patient's femur and allows a connectorportion of the post to remain accessible at step 408. The Surgeon thenat step 410 affixes the knee alignment solution primary sensor to theconnector. The primary sensor and connector can have a narrow profile onthe order of less than 2×6×8 inches (W,L,H). The tall and slim profilekeeps the electronics and sensor housing up vertically away from thelateral, medial, anterior and posterior surgical areas. At step 412, theSurgeon places the secondary sensor to a fixed location with aline-of-sight view of the primary sensor. At step 414, the surgical teaminitiates software to initiate hip center (femur head) identification.

The Surgeon rotates patients femur at step 416 so primary sensor locatespatient's hip center. At step 418, the system indicates when a hipcenter has been located and its absolute and relative position to theprimary sensor. Referring to FIG. 5A, a communication network 500 foralignment detection and reporting is shown. Briefly, the communicationnetwork 500 expands broad data connectivity to other devices orservices. As illustrated, the alignment detection and reporting system555 can be communicatively coupled to the communications network 500 andany associated systems or services.

As one example, the alignment system 555 can share its parameters ofinterest (e.g., angles, alignment, displacement, movement, rotation, andacceleration) with remote services or providers, for instance, toanalyze or report on surgical status or outcome. This data can be sharedfor example with a service provider to monitor progress or with planadministrators for surgical monitoring purposes or efficacy studies. Thecommunication network 500 can further be tied to an Electronic MedicalRecords (EMR) system to implement health information technologypractices. In other embodiments, the communication network 500 can becommunicatively coupled to HIS Hospital Information System, HIT HospitalInformation Technology and HIM Hospital Information Management, EHRElectronic Health Record, CPOE Computerized Physician Order Entry, andCDSS Computerized Decision Support Systems. This provides the ability ofdifferent information technology systems and software applications tocommunicate, to exchange data accurately, effectively, and consistently,and to use the exchanged data.

The communications network 500 can provide wired or wirelessconnectivity over a Local Area Network (LAN) 501, a Wireless Local AreaNetwork (WLAN) 505, a Cellular Network 514, and/or other radio frequency(RF) system (see FIG. 4). The LAN 501 and WLAN 505 can becommunicatively coupled to the Internet 520, for example, through acentral office. The central office can house common network switchingequipment for distributing telecommunication services. Telecommunicationservices can include traditional POTS (Plain Old Telephone Service) andbroadband services such as cable, HDTV, DSL, VoIP (Voice over InternetProtocol), IPTV (Internet Protocol Television), Internet services, andso on.

The communication network 500 can utilize common computing andcommunications technologies to support circuit-switched and/orpacket-switched communications. Each of the standards for Internet 520and other packet switched network transmission (e.g., TCP/IP, UDP/IP,HTML, HTTP, RTP, MMS, SMS) represent examples of the state of the art.Such standards are periodically superseded by faster or more efficientequivalents having essentially the same functions. Accordingly,replacement standards and protocols having the same functions areconsidered equivalent.

The cellular network 514 can support voice and data services over anumber of access technologies such as GSM-GPRS, EDGE, CDMA, UMTS, WiMAX,2G, 3G, WAP, software defined radio (SDR), and other known technologies.The cellular network 514 can be coupled to base receiver 510 under afrequency-reuse plan for communicating with mobile devices 502.

The base receiver 510, in turn, can connect the mobile device 502 to theInternet 520 over a packet switched link. The internet 520 can supportapplication services and service layers for distributing data from theload sensing system 555 to the mobile device 502. The mobile device 502can also connect to other communication devices through the Internet 520using a wireless communication channel.

The mobile device 502 can also connect to the Internet 520 over the WLAN505. Wireless Local Access Networks (WLANs) provide wireless accesswithin a local geographical area. WLANs are typically composed of acluster of Access Points (APs) 504 also known as base stations. The loadsensing system 555 can communicate with other WLAN stations such aslaptop 503 within the base station area. In typical WLANimplementations, the physical layer uses a variety of technologies suchas 802.11b or 802.11g WLAN technologies. The physical layer may useinfrared, frequency hopping spread spectrum in the 2.4 GHz Band, directsequence spread spectrum in the 2.4 GHz Band, or other accesstechnologies, for example, in the 5.8 GHz ISM band or higher ISM bands(e.g., 24 GHz, etc).

By way of the communication network 500, the alignment system 555 canestablish connections with a remote server 530 on the network and withother mobile devices for exchanging data. The remote server 530 can haveaccess to a database 540 that is stored locally or remotely and whichcan contain application specific data. The remote server 530 can alsohost application services directly, or over the internet 520.

FIG. 5B shows one embodiment of the communication network 500 formanaging smart implant products, services and applications. A smartimplant for example can identify alignment, joint movement, bonedensity, load forces and temperature data. This information can beconveyed via wireless services, for example, over a telecommunicationnetwork to event service providers. The event services can includeorthopedic implant and patient event services for time critical, secure,and reliable messaging and reporting. This information is related tomonitoring services responsible for medical reporting, patient/doctorand consulting offices, and research services, including medical deviceand pharmaceutical companies.

FIG. 6 depicts an exemplary diagrammatic representation of a machine inthe form of a computer system 600 within which a set of instructions,when executed, may cause the machine to perform any one or more of themethodologies discussed above. In some embodiments, the machine operatesas a standalone device. In some embodiments, the machine may beconnected (e.g., using a network) to other machines. In a networkeddeployment, the machine may operate in the capacity of a server or aclient user machine in server-client user network environment, or as apeer machine in a peer-to-peer (or distributed) network environment.

The machine may comprise a server computer, a client user computer, apersonal computer (PC), a tablet PC, a laptop computer, a desktopcomputer, a control system, a network router, switch or bridge, or anymachine capable of executing a set of instructions (sequential orotherwise) that specify actions to be taken by that machine. It will beunderstood that a device of the present disclosure includes broadly anyelectronic device that provides voice, video or data communication.Further, while a single machine is illustrated, the term “machine” shallalso be taken to include any collection of machines that individually orjointly execute a set (or multiple sets) of instructions to perform anyone or more of the methodologies discussed herein.

The computer system 600 may include a processor 602 (e.g., a centralprocessing unit (CPU), a graphics processing unit (GPU, or both), a mainmemory 604 and a static memory 606, which communicate with each othervia a bus 608. The computer system 600 may further include a videodisplay unit 610 (e.g., a liquid crystal display (LCD), a flat panel, asolid state display, or a cathode ray tube (CRT)). The computer system600 may include an input device 612 (e.g., a keyboard), a cursor controldevice 614 (e.g., a mouse), a disk drive unit 616, a signal generationdevice 618 (e.g., a speaker or remote control) and a network interfacedevice 620.

The disk drive unit 616 may include a machine-readable medium 622 onwhich is stored one or more sets of instructions (e.g., software 624)embodying any one or more of the methodologies or functions describedherein, including those methods illustrated above. The instructions 624may also reside, completely or at least partially, within the mainmemory 604, the static memory 606, and/or within the processor 602during execution thereof by the computer system 600. The main memory 604and the processor 602 also may constitute machine-readable media.

Dedicated hardware implementations including, but not limited to,application specific integrated circuits, programmable logic arrays andother hardware devices can likewise be constructed to implement themethods described herein. Applications that may include the apparatusand systems of various embodiments broadly include a variety ofelectronic and computer systems. Some embodiments implement functions intwo or more specific interconnected hardware modules or devices withrelated control and data signals communicated between and through themodules, or as portions of an application-specific integrated circuit.Thus, the example system is applicable to software, firmware, andhardware implementations.

In accordance with various embodiments of the present disclosure, themethods described herein are intended for operation as software programsrunning on a computer processor. Furthermore, software implementationscan include, but not limited to, distributed processing orcomponent/object distributed processing, parallel processing, or virtualmachine processing can also be constructed to implement the methodsdescribed herein.

The present disclosure contemplates a machine readable medium containinginstructions 624, or that which receives and executes instructions 624from a propagated signal so that a device connected to a networkenvironment 626 can send or receive voice, video or data, and tocommunicate over the network 626 using the instructions 624. Theinstructions 624 may further be transmitted or received over a network626 via the network interface device 620.

While the machine-readable medium 622 is shown in an example embodimentto be a single medium, the term “machine-readable medium” should betaken to include a single medium or multiple media (e.g., a centralizedor distributed database, and/or associated caches and servers) thatstore the one or more sets of instructions. The term “machine-readablemedium” shall also be taken to include any medium that is capable ofstoring, encoding or carrying a set of instructions for execution by themachine and that cause the machine to perform any one or more of themethodologies of the present disclosure.

The term “machine-readable medium” shall accordingly be taken toinclude, but not be limited to: solid-state memories such as a memorycard or other package that houses one or more read-only (non-volatile)memories, random access memories, or other re-writable (volatile)memories; magneto-optical or optical medium such as a disk or tape; andcarrier wave signals such as a signal embodying computer instructions ina transmission medium; and/or a digital file attachment to e-mail orother self-contained information archive or set of archives isconsidered a distribution medium equivalent to a tangible storagemedium. Accordingly, the disclosure is considered to include any one ormore of a machine-readable medium or a distribution medium, as listedherein and including art-recognized equivalents and successor media, inwhich the software implementations herein are stored.

Although the present specification describes components and functionsimplemented in the embodiments with reference to particular standardsand protocols, the disclosure is not limited to such standards andprotocols. Each of the standards for Internet and other packet switchednetwork transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP) representexamples of the state of the art. Such standards are periodicallysuperseded by faster or more efficient equivalents having essentiallythe same functions. Accordingly, replacement standards and protocolshaving the same functions are considered equivalents.

The illustrations of embodiments described herein are intended toprovide a general understanding of the structure of various embodiments,and they are not intended to serve as a complete description of all theelements and features of apparatus and systems that might make use ofthe structures described herein. Many other embodiments will be apparentto those of skill in the art upon reviewing the above description. Otherembodiments may be utilized and derived therefrom, such that structuraland logical substitutions and changes may be made without departing fromthe scope of this disclosure. Figures are also merely representationaland may not be drawn to scale. Certain proportions thereof may beexaggerated, while others may be minimized. Accordingly, thespecification and drawings are to be regarded in an illustrative ratherthan a restrictive sense.

What is claimed is:
 1. A sensor for a surgical orthopedic alignmentsystem comprising: at least two ultrasonic transducers located atpredetermined positions on the sensor; an accelerometer; and acontroller operatively coupled to the at least two ultrasonictransducers and the accelerometer to determine a location of an objectin three-dimensional space within a surgical field from one or moresignals received thereto.
 2. The sensor of claim 1 where the sensorfurther includes a mounting structure to attach the sensor in areference position.
 3. The sensor of claim 2 where the mountingstructure includes a threaded portion for attaching to a bone.
 4. Thesensor of claim 2 where the mounting structure attaches to a cuttingblock or jig.
 5. The sensor of claim 3 where the sensor furtherincludes: a printed circuit board; and the at least two ultrasonictransducers coupled to a first side of the printed circuit board whereeach of the at least two ultrasonic transducers have a predeterminedlocation on the printed circuit board for receiving signals directedthereto.
 6. The sensor of claim 5 where a second side of the printedcircuit board includes at least three ultrasonic transducers each at apredetermined location on the second side of the printed circuit boardfor receiving signals directed thereto.
 7. The sensor of claim 1 furtherincluding an optical detector for receiving an optical trigger signal.8. The sensor of claim 1 further including: a power source coupled forpowering the sensor; and wireless communication circuitry coupled to thecontroller for transmitting alignment information.
 9. The sensor ofclaim 1 where the at least two transducers are covered with a materialtransmissive to ultrasonic frequencies.
 10. The sensor of claim 1 wherethe sensor includes a user interface coupled to the controller that canvisually or audibly report a status.
 11. A wand for a surgicalorthopedic alignment system comprising: at least two ultrasonictransducers located at predetermined positions on the wand; anaccelerometer; and a controller operatively coupled to the at least twoultrasonic transducers and the accelerometer to identify a location ofan object in three-dimensional space within a surgical field by sendingultrasonic signals therefrom.
 12. The wand of claim 11 furtherincluding: a housing operatively formed for being handheld; and a tipextending from the housing for registering one or more locations. 13.The wand of claim 12 where the tip is a touch sensitive tip that isresponsive to a physical action.
 14. The wand of claim 11 furtherincluding an optical emitter to send an optical trigger signal.
 15. Thewand of claim 11 further including a mount in a predetermined locationwhere the mount retains the wand in the predetermined location during aportion of an alignment procedure.
 16. The wand of claim 11 furtherincluding: a power source internal to the wand coupled for powering thewand; a user interface coupled to the controller that can visually oraudibly report a status; and wireless communication circuitry coupled tothe processor for transmitting information.
 17. The wand of claim 11further including an attachment mechanism to mount the wand to a bone orcutting block or jig.
 18. A surgical orthopedic alignment systemcomprising: a wand having at least two ultrasonic transducers totransmit signals corresponding to a location in three-dimensional space;a sensor having at least two ultrasonic sensors to receive signals fromthe wand; a trigger system between the wand the sensor that initiates atime of flight and a differential time of flight measurement; and amount to retain and hold the wand in a predetermined location where thewand, sensor, and mount are within a surgical field.
 19. The alignmentsystem of claim 18 where the sensor and the wand are disposable.
 20. Thealignment system of claim 19 further including a display coupled tosensor and wand outside the surgical field.